Vibration demonstrator

ABSTRACT

An educational device for observing the physical characteristics of a vibrating mass comprises a generally planar shaped support base from which an elongated resilient body is supported in a parallel spaced apart plane, a receptacle mounted to the elongated body for receiving materials of different mass and an indicating means also supported from the base and proportioned with respect to the receptacle for providing an indication of movement of the receptacle through an equilibrium position when the resilient body is deflected and caused to vibrate.

United States Patent Stehl [54] VIBRATION DEMONSTRATOR [72] Inventor:George StehI, Kew Gardens, NY.

[73] Assignee: Xerox Corporation, Rochester,

[22] Filed: May 19, 1971 21 Appl. No.: 144,935

[52] US. Cl. ..35/ 19 R [51] Int. Cl. ..G09b 23/08 [58] Field of Search..35/l9 R; 73/70, 70.2; 46/1 C [56] References Cited FOREIGN PATENTS ORAPPLICATIONS 127,321 3/1932 Austria .,...73/70 403,484 12/1933GreatBritain ..35/l9R OTHER PUBLICATIONS Vibration Demonstrator page327, of Welch 1 Sept. 5, 1972 Scientific Co. Catalog Second Law ofMotion Apparatus" page 131 of Stansi Scientific Divr PrimaryExaminer-Harland S. Skogquist Attorney-James J. Ralabate, WilliamKaufman and Barry Kramer [57] ABSTRACT An educational device forobserving the physical characteristics of a vibrating mass comprises agenerally planar shaped support base from which an elongated resilientbody is supported in a parallel spaced apart plane, a receptacle mountedto the elongated body for receiving materials of different mass and anindicating means also supported from the base and proportioned withrespect to the receptacle for providing an indication of movement of thereceptacle through an equilibrium position when the resilient body isdeflected and caused to vibrate.

8Claims,5DrawingFigures VIBRATION DEMONSTRATOR This invention relates toeducational devices. The invention relates more particularly to aneducational device for demonstrating the physical properties of avibrating mass.

It is desirable to provide a device in educational systems fordemonstrating various physical properties associated with a vibratingmass. For example, in the Process Approach to scientific education atgrade school level as proposed by the American Association for theAdvancement of Science, an exercise is suggested for providing anoperational definition of mass. In this exercise, the mass of avibrating body is altered in order to demonstrate inertia attributableto masses of different magnitudes and ultimately to aid the student informulating a concept of mass. An educational device of this type isdesirably relatively non-complex and rugged in design and readilyportable for transport from location to location. Additionally, itisfurther desirable that the device include means for receiving bodiesof difierent masses and in accordance with the technique of theexercise, provide a means for indicating the number of vibrations of themass about a reference point during an interval of time.

Accordingly, it is an object of this invention to provide an educationaldevice for demonstrating physical properties associated with the mass ofa body.

Another object of the invention is to provide an educational device ofthe type described which is relatively non-complex, rugged and readilyportable.

In accordance with the features of this invention, an educational devicefor observing the physical characteristics of a vibrating mass comprisesa generally planar shaped support base from which an elongated resilientbody is supported in a parallel spaced apart plane, a receptacle mountedto the elongated body for receiving materials of different mass and anindicating means also supported from the base and positioned withrespect to the receptacle for providing an indication of movement of thereceptacle through an equilibrium position when the resilient body isdeflected and caused to vibrate.

These and other objects and features of the invention will becomeapparent with reference to the following specification and to thedrawings wherein:

FIG. 1 is a perspective view of the educational device of this inventionshown mounted on planar support surface and illustrating a massreceptacle in a deflected position for initiating vibrations of thereceptacle;

FIG. 2 is a plan view of the educational device of FIG. 1 illustratingthe mass receptacle in its furthermost deflected position and at itsequilibrium position;

FIG. 3 is a view taken along lines 3-3 of FIG. 2;

FIG. 4 is a view taken along lines 4-4 of FIG. 3; and,

FIG. 5 is a bottom view of a portion of the support base illustrating amounting means for an audible oscillation indicator.

Referring now to FIG. 1, the educational device in accordance with thefeatures of this invention is shown to comprise an elongated generallyplanar shaped support base 10 which is mounted on a table-top surface 12for example, by a suction mounting means represented generally as 14.The support base 10 which is preferably formed of plastic has integrallymolded therewith a support means comprising a post 16 extending from thesupport base in a direction which is generally perpendicular to theplane of the base 10. The post 16 supports an elongated rectilinearshaped resilient body 18 which is preferably formed of a strip of metalsuch as spring steel and which has a length which is substantial greaterthan a width of this body.

The resilient body 18 is supported at one end thereof on the post 16 byscrews 20 and 22 which extend through the post and through aperturesformed in the end of the body 18 and are secured to the post byassociated nuts. The body 18 is centrally located within the interior ofthe post by spaces 24 and 26.

A receptacle 28 is provided and is mounted to another end of the body 18for supporting bodies 30 and 32 of different masses. The receptacle ismounted to the resilient body 18 by screws 34 and 36 which extendthrough apertures in the body 18 and through apertures in a handlesegment 38 of the receptacle 28. As illustrated in FIG. 2, thereceptacle 28 and the resilient body 18 can be deflected from anequilibrium position to a deflection position from which location it isreleased and will vibrate or oscillate about the equilibrium position ata frequency corresponding to the mass of the receptacle and itscontents. A deflection limiting member 40 is provided for establishing areference station for deflection of the resilient body 18 in order thatthe receptacle 28 and its contents will be released from a station whichprovides the same amplitude of deflection from the equilibrium positionfor all tests. The limiting body is shown to be integrally molded withthe support base 10 and includes a canted surface 42 which conforms tothe shape of the resilient body 18 when deflected from its equilibriumposition.

In order to indicate the frequency of oscillation or vibration of thereceptacle and its contents, a vibration indicating means is providedand ispositioned on the support base 10. The vibration indicating meansis shown to include a body formed from a strip of thin plastic material50 having an upstanding segment 52 which is positioned in the path ofthe receptacle 28. The plastic body 50 is supported by an integrallymolded support body 54 having a plurality of studs 56 [FIG. 5] dependingfrom an inner lower surface of the body 54. The indicator body 50extends through an entrance aperture 58 in the body 54 and is guided inan offset path between the posts 56 which confine and restrain thisindicating body. The body 50 is formed of a plastic material having athickness which provides for deflection of the segment 52 when thereceptacle 28 is released from its deflected position and oscillatesabout its equilibrium position. During each traversal of the equilibriumposition during oscillation, the receptacle 28 will deflect the segment52 thereby causing a clearly distinguishable sound useful in countingthe number of traversals in a period of time and for determining thefrequency or period of oscillation.

The educational device is mounted to a support surface 12 by the vacuummounting means 14. Channels 60 [FIG. 3] which are formed in the basemember 10 engage extending shoulders 62 of an upper surface on a housing64 of the vacuum mounting means 14. A tab segment 66 of the base 10extends through a window 68 in the vacuum mounting means 14 and engagesthe window frame for locking the educational device to the vacuum mount.The educational device can be demounted by depressing the tab 66 andsimultaneously withdrawing the base from the vacuum mount 14. The device10 is therefore conveniently demountable from the vacuum mount fortransporting from location to location and alternatively the entire unitcan be demounted from the surface 12 by rotation of a lever arm '70which operates on a surface 72 of the vacuum mount to release thevacuum. A vacuum mount of this type is shown and described in detail andis claimed in a copending US. patent application which is filedconcurrently herewith and which is assigned to the assignee of thisinvention.

in operation, a body of particular mass is positioned in the receptacle;the receptacle is deflected to the surface 42 and released; and, thebody is allowed to vibrate. The number of vibrations are counted bylistening to the audible clicks for a predetermined interval of time.Bodies of different masses can be positioned in the receptacle anddeflected in order to demonstrate frequency of vibration is inverselyproportional to mass. In a particular exercise as proposed by theAmerican Association for the Advancement of Science, a number ofmetallic washers are placed in the receptacle 28 and the number ofvibrations for a predetermined period of time is plotted versus thenumber of washers in the receptacle. Students then formulate a conceptof mass magnitude in terms of a number of particular units such as thewashers. The mass of unknown bodies such as small stones and the likecan be determined by vibrating these bodies in the receptacle and theequivalent number of washers is obtained from the curve of washersversus frequency. As this exercise progresses, the curve is calibratedin grams by vibrating bodies 30 and 32 of known mass. This exercise isexplained in detail in ScienceA Process Approach/Part F, Definingoperationally Inertia and Mass published by the American Association forthe Advancement of Science.

An educational device for observing the physical characteristics of avibrating mass has thus been described which is advantageouslyrelatively non-complex and rugged, relatively low in cost, and which isadapted to receive bodies of different masses.

While we have illustrated and described a particular embodiment of ourinvention, it will be understood that various modifications may be madetherein without departing from the spirit of the invention and the scopeof the appended claims.

an elongated generally planar shaped support base;

an elongated, rectilinear shaped resilient body having a width andhaving a length which is substantially greater than the width;

means extending from said support base in a direction generallyperpendicular to the plane of said base for supporting said resilientbody at one end of the resilient body in a plane generally parallel toand spaced apart from said support base whereby deflection of saidresilient body from an equilibrium position and release thereof causesvibration of the body about the equilibrium posia re ptacle rigidlymounted to said resilient body at another end thereof for receiving andretaining during vibrations material of differing mass; and,

vibration indicating means positioned on said support base and actuatedduring movement of said receptacle for providing an indication ofmovement of said receptacle through the equilibrium position when saidresilient body and receptacle are vibrated.

2. The device of claim 1 wherein a limiting body is provided and extendsfrom said base limiting the deflection of said resilient body from theequilibrium position.

3. The device of claim 2 wherein said support base, said means forsupporting said resilient body and said limiting body are integrallymolded of a plastic material.

4. The device of claim 1 wherein said resilient body is formed of astrip of metal.

5. The device of claim 1 wherein said vibration indicating means isarranged to provide an audible indication.

6. The device of claim 5 wherein said audible indicating means comprisesa body of material which is mounted on said base and positioned fordeflection by the receptacle when said vibrating receptacle traversesthe equilibrium position of said resilient body.

7. The device of claim 5 wherein said audible indicating means issupported on said base and positioned for deflection by said resilientbody when said vibrating resilient body transverses the equilibriumposition.

8. The device of claim 5 wherein said audible indicating means comprisesa thin plastic body which is supported on the base and positioned in thepath of the moving receptacle for deflection thereby, said indicatingbody having a thickness for providing an audible sound when deflected.

1. An educational device for observing the physical characteristics of avibrating mass comprising: an elongated generally planar shaped supportbase; an elongated, rectilinear shaped resilient body having a width andhaving a length which is substantially greater than the width; meansextending from said support base in a direction generally perpendicularto the plane of said base for supporting said resilient body at one endof the resilient body in a plane generally parallel to and spaced apartfrom said support base whereby deflection of said resilient body from anequilibrium position and release thereof causes vibration of the bodyabout the equilibrium position; a receptacle rigidly mounted to saidresilient body at another end thereof for receiving and retaining duringvibrations material of differing mass; and, vibration indicating meanspositioned on said support base and actuated during movement of saidreceptacle for providing an indication of movement of said receptaclethrough the equilibrium position when said resilient body and receptacleare vibrated.
 2. The device of claim 1 wherein a limiting body isprovided and extends from said base limiting the deflection of saidresilient body from the equilibrium position.
 3. The device of claim 2wherein said support base, said means for supporting said resilient bodyand said limiting body are integrally molded of a plastic material. 4.The device of claim 1 wherein said resilient body is formed of a striPof metal.
 5. The device of claim 1 wherein said vibration indicatingmeans is arranged to provide an audible indication.
 6. The device ofclaim 5 wherein said audible indicating means comprises a body ofmaterial which is mounted on said base and positioned for deflection bythe receptacle when said vibrating receptacle traverses the equilibriumposition of said resilient body.
 7. The device of claim 5 wherein saidaudible indicating means is supported on said base and positioned fordeflection by said resilient body when said vibrating resilient bodytransverses the equilibrium position.
 8. The device of claim 5 whereinsaid audible indicating means comprises a thin plastic body which issupported on the base and positioned in the path of the movingreceptacle for deflection thereby, said indicating body having athickness for providing an audible sound when deflected.